Navigating a vehicle through its environment poses a number of problems, particularly for autonomous robots. Presently there are a number of navigation systems which rigidly define paths the robot must follow.
One system utilizes a cable, tape or other track which is laid across the ground. The robot must follow that track and cannot deviate from it. This presents problems when obstacles appear across the path.
Another system uses spot markers such as glass bubbles which are placed along the floor along a path. The bubbles are highly reflective and reflect incident light which is tracked by the robot.
Yet other systems follow laser beams or spotlight a target with infrared radiation or a laser beam. The robots then head toward that target.
Some robots utilize inertial reference systems to guide them among compass headings. Inertial reference is typically provided by a gyroscope. Accurate gyroscopes, particularly digitally readable ones, are quite expensive and are relatively delicate.
Navigation can also be accomplished by dead reckoning. Encoders on the drive system record the distance travelled by the wheels or tracks of the robot. This technique, also known as odometry, further includes steering encoders to record changes in orientation.
Other systems model the surrounding environment by reducing the environment to geometric features. The environment is typically modelled as a series of line segments representing surface features, or as a grid representing the probability of presence or absence of objects within particular locations. Paths such as S-curves are then plotted around the modelled features.